Deodorants are preparations which have antimicrobial activity and which mask, remove, or decrease perspiration odor. Antiperspirants are substances which have astringent action and inhibit the flow of perspiration. Salts of metals such as aluminum, zirconium, zinc, etc. have astringent properties and are often used in antiperspirants. Most of the antiperspirant salts which show good astringency properties have a low pH (2.5 to 4.2), which in turn makes them potentially irritating to skin in susceptible individuals. Antiperspirant/deodorant manufacturers often counteract the potentially irritating effects of low PH antiperspirant salts by including soothing materials such as emollients in the formulation. However, as the user sweats the emollients are washed away in a short time thus their soothing effects do not last as long as desired.
Microencapsulation technology is well known in the art and is generally directed to encapsulating core materials that require protection until time of use in a protective covering. More recently microcapsules have been developed which are "time release". Time release microcapsules release their core materials at a controlled rate. The result is that the core material has a longer effective life since it is not immediately released from the protective microcapsule. The benefits of controlled release are obvious. For example, when pharmaceuticals are in the controlled release format, it generally allows the user to ingest or apply one long acting dose of drug instead of being obliged to ingest many small doses throughout a time period.
The encapsulation of fragrances is well known in the art. Fragrance capsules are often found in scratch and sniff inserts in magazines, in perfumes, deodorants, and a host of other applications. In the case of antiperspirants the desireability of microcapsules containing a soothing emollient is obvious. Timed release of the emollient from the microcapsule will allow its beneficial effects to have a longer effective life. This will in turn potentially counteract the irritating effects of antiperspirant salts in sensitive individuals.